In many present day military applications of guided missiles, the space requirements for a missile, due to wingspan, become an imposing factor. For example, the Penguin missile is a surface-to-surface weapon currently in the possession of a number of national navies. The missile is stored and launched from a canister approximately 43 inches.times.43 inches due to the relatively large wingspan of 1.49 meters. As will be appreciated, when storing a number of these missiles in canisters, the pressure of storage space becomes a primary concern. This is particularly the case when missiles of this sort are adapted for use by aircraft such as helicopters. If a relatively large missile with the corresponding necessarily large wingspan is to be employed, it has been recognized that a folding wing configuration must be designed to provide clearance with the ground plane and to provide a reasonable envelope when carried on an aircraft such as a helicopter.
If the folding wing configuration is to be employed, the fold mechanism must be enclosed within the wing contour and the wing deployment mechanism must be relatively lightweight and secure so that the wings will remain in a deployed position when a missile with the folding wing contour encounters air resistance and vibration after deployment.
The present assignee's copending patent application to Rosenberger, et al., entitled PENGUIN MISSILE FOLDING WING CONFIGURATION, filed Aug. 2, 1985, Ser. No. 764,457, 1985, offers an improved foldable wing configuration which employs a non-reversible mechanism dependent upon overcenter action. To operate the mechanism a pyrotechnic actuator is fired which displaces the overcenter mechanism to which the wing structure is attached. The use of such an actuator ensures a rapid certain deployment of the foldable wings to a non-reversible position.
Although assignee's copending application will operate generally satisfactorily, the use of a pyrotechnic device for actuating wing deployment suffers disadvantages, namely, safety, stowage, and an impulse actuation load on the overcenter deployment linkage which may adversely affect the performance characteristics of the deployment mechanism. Accordingly, it would be desirable to implement an actuating mechanism which exhibits a more linear actuating load on the deployment mechanism. A further problem with the utilization of pyrotechnic actuating devices is their performance variation with temperature, which poses a design concern.